The present invention relates to an article holding apparatus of rotary type and more particularly to an improved apparatus for firmly holding a plurality of articles in the form of a bottle container or the like on supporting mechanisms for the purpose of inspecting, labelling, painting or the like, wherein the supporting mechnisms rotatably held on a rotating means in the form of a rotary table, a plurality of radially extending holding arms for holding the respective articles or the like are caused to rotate about the center axis thereof while they revolve round the center axis of the rotating means.
A hitherto known bottle inspecting apparatus of rotary type is generally constructed such that inspection is performed as to whether or not any damage or injury takes place with bottle containers (hereinafter referred to simply as bottle) conveyed from the preceding process or any foreign material is stuck onto their surfaces while the bottles revolving round the center axis of the rotary table are caused to rotate about their own center axis after they enter an inspecting section where an optical instrument is provided. The optical instrument generally has a light source disposed in a position opposite to the barrel portion of each bottle to be inspected and a plurality of light-receiving elements for receiving the light transmitting through the bottle. To allow the bottles to rotate about their own center axis in the inspecting section the conventional bottle inspecting apparatus is usually equipped with an arm gripper or the like means which is adapted to hold each of the bottles at their barrel portion to rotate it. However, it is pointed out as a drawback inherent to the conventional bottle inspecting apparatus of the above kind that the arrangement of the arm grippers in the inspecting area inhibits smooth inspecting operation for the whole surface of the respective bottles because the arm grippers shield the light emitted by the light source.
The conventional bottle rotating mechanism includes a sun gear and a pinion both of which are in meshing engagement with one another, said pinion being fixedly fitted onto a support adapted to rotatably hold a bottle to be inspected. As the pinion rolls round the periphery of the sun gear while they mesh with one another, the bottle is caused to rotate about the same center axis as that of the pinion.
However, due to the arrangement of the sun gear meshing directly with the plural pinion gears disposed at an equal distance along the periphery of a circle, noisy sound is generated during the operation of the gears. Further, due to the arrangement of no slippage taking place in the power transmission system, no smooth power transmission is achieved, resulting in quick starting and stopping of rotation of the bottles. Thus, the bottles are held on the rotary table unstably. Another drawback of the conventional bottle inspecting apparatus of this kind including the sun gear and the plural pinions is that a complicated clutching mechanism is required when the bottle rotating section is defined within a part of the periphery of the revolving circle.